3.1 Heart Failure & Cardiogenic Shock

Heart Failure & Cardiogenic Shock

Heart failure (HF) and its most severe complication, cardiogenic shock, sit at the center of the PCCN cardiovascular blueprint. The progressive care nurse must recognize decompensation early, understand the hemodynamics driving symptoms, and titrate therapy to restore adequate perfusion without worsening the underlying pump problem.

Preload, Afterload & Contractility

Cardiac output depends on three variables the exam expects you to reason through together:

• Preload — the volume stretching the ventricle before contraction (reflected by CVP on the right, PCWP/PAOP on the left). Too little preload (hypovolemia) drops output; too much (volume overload) causes pulmonary or systemic congestion.
• Afterload — the resistance the ventricle must overcome to eject blood (systemic vascular resistance for the left ventricle, pulmonary vascular resistance for the right). Hypertension and vasoconstriction raise afterload and worsen a failing pump.
• Contractility — the intrinsic force of ventricular contraction, reduced in systolic (HFrEF) heart failure and relatively preserved in diastolic (HFpEF) heart failure.

BNP or NT-proBNP is released from stretched ventricular myocardium and is the key lab used to distinguish cardiac dyspnea from a primary pulmonary cause — a markedly elevated BNP in a breathless patient points toward heart failure rather than pneumonia or COPD.

Acute Decompensated Heart Failure & Pulmonary Edema

When the left ventricle can no longer keep up with venous return, pressure backs up into the pulmonary circulation. Classic findings include:

• Sudden dyspnea, orthopnea, and paroxysmal nocturnal dyspnea
• Bibasilar crackles, an S3 gallop, and pink, frothy sputum in severe cases
• Anxiety, diaphoresis, and use of accessory muscles
• Jugular venous distension and peripheral edema if right-sided congestion coexists

Priority interventions target preload reduction and oxygenation: high-flow oxygen or non-invasive ventilation (CPAP/BiPAP) to reduce work of breathing and improve gas exchange, IV loop diuretics (furosemide, bumetanide) to offload volume, IV nitroglycerin to reduce preload and afterload, and upright positioning with legs dependent to reduce venous return. Morphine is used sparingly today because it can blunt respiratory drive and lower blood pressure; it is no longer first-line.

Chronic Heart Failure Management

Stable outpatients with HFrEF are managed on guideline-directed medical therapy, sometimes called the "four pillars": an ACE inhibitor, ARB, or ARNI (sacubitril-valsartan); a beta-blocker proven in HF (carvedilol, metoprolol succinate, or bisoprolol); a mineralocorticoid receptor antagonist (spironolactone, eplerenone); and an SGLT2 inhibitor (dapagliflozin, empagliflozin). Loop diuretics control congestion symptomatically but do not alter mortality. Nursing surveillance includes daily weights (a gain of 2–3 lb in a day or 5 lb in a week signals fluid retention), sodium and fluid restriction education, and monitoring potassium and renal function on RAAS-blocking drugs.

Cardiogenic Shock

Cardiogenic shock is the end-stage manifestation of pump failure and the classic "hypotensive, cold, low-output" shock state the PCCN blueprint tests directly. It is most commonly triggered by a large anterior MI but can also follow decompensated chronic HF, myocarditis, or valve rupture.

Recognize it by:

• Systolic blood pressure < 90 mmHg (or a drop of ≥ 30 mmHg from baseline) sustained despite adequate volume
• Cool, clammy, mottled extremities with diminished peripheral pulses
• Oliguria (urine output < 30 mL/hr) from poor renal perfusion
• Altered mental status from cerebral hypoperfusion
• Hemodynamically: cardiac index < 2.2 L/min/m² with elevated pulmonary capillary wedge pressure (> 18 mmHg)

This "cold and wet" hemodynamic profile distinguishes cardiogenic shock from the "warm" distributive shock states (septic, anaphylactic) covered elsewhere in the blueprint — a distinction the exam rewards you for making quickly.

Treatment focuses on restoring perfusion while treating the cause. Inotropes such as dobutamine or milrinone increase contractility; norepinephrine is added when hypotension is severe to maintain coronary and cerebral perfusion pressure. Emergent revascularization (PCI or CABG) is definitive therapy when an acute MI is the trigger. When pharmacologic support is insufficient, mechanical circulatory support devices — the intra-aortic balloon pump (IABP), percutaneous ventricular assist devices (Impella), or veno-arterial ECMO — unload the ventricle and augment output.

Ventricular Assist Devices (VADs)

Durable LVADs support patients with end-stage HF as a bridge to transplant or destination therapy. Because most LVADs produce continuous, non-pulsatile flow, a standard cuff blood pressure and pulse oximetry may be unreliable or absent; mean arterial pressure is obtained by Doppler, and the goal MAP is typically 70–90 mmHg. Nurses must monitor the driveline exit site closely for infection (a leading LVAD complication), assess for GI bleeding (LVAD flow causes an acquired von Willebrand factor deficiency and predisposes to arteriovenous malformations), and recognize pump alarms indicating suction events (from hypovolemia) or thrombosis (from rising power consumption).

Understanding where a patient sits on the preload/afterload/contractility continuum — and matching the intervention to that physiology — is the clinical-reasoning skill the PCCN exam is built to test in this content area.

Right-Sided Heart Failure

Left-sided failure is the more commonly tested scenario, but right ventricular failure — whether from chronic left heart disease, pulmonary hypertension, or a right ventricular infarct — produces its own distinct picture: jugular venous distension, hepatomegaly, ascites, and dependent peripheral edema, with lungs that may remain clear. A right ventricular MI deserves special attention because these patients are preload-dependent: nitrates and diuretics, which reduce preload, can precipitate profound hypotension, so fluid boluses rather than diuresis are often the first-line response when a right-sided infarct is suspected on a 12-lead with right-sided leads.